aws-arn

This library provides a type representing Amazon Resource Names (ARNs), and parsing/unparsing functions for them. When combined with generic-lens or generic-optics, the provided prisms make it very convenient to rewrite parts of ARNs.

Start reading at the Network.AWS.ARN module, which defines the core data type and includes some examples.

The ARN type is not designed to be a 100% correct-by-construction representation of only valid ARNs; it is designed to be a lightweight way to destructure and reassemble ARNs to be used in place of string munging.

The library aims to provide additional parsers for destructuring the "resource" part of an ARN, but many are missing right now. PRs to add this support for more AWS resource types are especially welcome.

Guide: adding a resource

Cribbing from an existing module (e.g., Network.AWS.ARN.Lambda) is probably the easiest way to start, but here is an explicit process to add a new resource:

1. Create a module for the AWS service, if it doesn't already exist. Example: src/Network/AWS/ARN/Lambda.hs.

2. Define a record Foo to represent the parsed resource part of an ARN, and derive (at least) Eq, Ord, Hashable, Show and Generic:

   data Function = Function
   { name :: Text,
     qualifier :: Maybe Text
   }
   deriving (Eq, Ord, Hashable, Show, Generic)

3. Define parseFoo and renderFoo functions that attempt to parse and unparse the resource part of the ARN:

   parseFunction :: Text -> Maybe Function
   renderFunction :: Function -> Text

   Remark: If you need to write tests for these functions, the corresponding module should live at test/Network/AWS/ARN/SomeAWSService/Test.hs

4. Define a _Foo Prism' that combines the parsing/unparsing functions above. Use the local definitions of prisms in Network.AWS.ARN.Internal.Lens:

   _Function :: Prism' Text Function
   _Function = prism' fromFunction toFunction

5. Add the records, their fields, its parsing/unparsing functions, and prisms to the service module's export list:

   module Network.AWS.ARN.Lambda
     ( -- * Functions
       Function (..),
       parseFunction,
       renderFunction,
   
       -- ** Prisms
       _Function,
     )

6. Test your work and make a PR.

Formatting code

The formatters used in this repo are provided by shell.nix:

• *.hs: ormolu
• *.cabal: cabal-fmt (cabal-fmt --inplace aws-arn.cabal)
• *.nix: nixpkgs-fmt (nixpkgs-fmt *.nix)

Regenerating CI

This repo uses haskell-ci, which is provided by shell.nix:

haskell-ci regenerate

Fixing CI not being able to install tools

So you ran the above command but haskell-ci couldn't install one of its tools (e.g. hlint, doctest) due to version incompatibilities. haskell-ci selects particular versions by default, but this can be changed with command line flags (e.g. --hlint-version '>=3.5 && <3.6', --doctest-version ==0.20.1). If you do this, please check haskell-ci; if the HEAD version does not select the latest version of a tool, please contribute a PR to that repository.